SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '558c519db3a87393a34eed951bd166c1c5c1a75963b3cc0a5bbc9157477db938' 
  AND token = 'SZTpQYr1K9QRhP7+S0AVbPeZIIQnmVvspXyHWZvPRYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}